The brown dog tick whose technical name is Rhipicephalus sanguineus has become an increasingly severe problem in recent years. Several forms of the same tick are seen, which often leads to confusion as people tend to think different species are involved.
A careful study of the life cycle diagram will show several different life stages. Adult female ticks engorged with blood are large and easy to find (11 to 12 mm by 6 to 7 mm). They are grey or brown in color, firm to touch, like sacs of fluid and have four pairs of short legs.
Adult males are much smaller, almost triangular in shape, with relatively longer legs and are reddish-brown in color. They are often found attached at the same site and in close approximation to the females.
Nymphal ticks are much smaller (1 to 2 mm) as are freshly hatched larval ticks (0.5 to 1 mm) which may be seen crawling out of cracks and down walls. Larval ticks have only three pairs of legs.
More than a dozen species of tick exist in the U.S. which may infest dogs, from time to time. However, most will only infest their specific host. Thus it is that the brown dog tick, Rhipicephalus is the one generally found on dogs. Of particular interest is the paralysis tick (Ixodes holocyclus) which is generally found on native fauna but can infest dogs causing paralysis and death.
Engorged females drop from the dog, and are often seen crawling across floors and up walls seeking concealed places to lay their eggs. One tick may produce about 3,000 eggs and then dies. The eggs hatch in about two and a half weeks in warm weather, or up to nine weeks in cold weather.
Hatched larvae quickly seek a dog, feed for about a week then drop off onto the ground where they molt into the next stage, known as nymphs. Nymphs also seek a dog, engorge on blood for a week then drop onto the ground where they molt into adults. Both larvae and nymphs can survive for several months before requiring a blood meal.
Adult females feed on the dog for several weeks before dropping off to lay eggs and die. They can survive for up to nineteen months without feeding. The minimum time before adult ticks appear on a dog after an engorged female has dropped off is about six weeks and the maximum time about two years.
Thus if an area is contaminated with ticks it is likely to remain infested for quite some time.
Ticks affect dogs by sucking blood, causing skin irritation and infection, and generally worrying and annoying the dog. Some allergic skin conditions are initiated by tick infestation. They are also of course a great nuisance to dog owners who find ticks in their houses. In overseas countries, dog ticks help the spread of several diseases.
The aim of any parasitic control system is to break the life cycle of the parasite. In the case of the brown dog tick, the best method appears to be in killing ticks on the dog by chemical washes.
- To achieve real success this process must be done regularly and thoroughly, otherwise, ticks will continue to infest the environment.
- A recommended method is weekly or twice weekly washing of the dog in an organic phosphate dip solution such as Asuntol, Bercotox or Suprex.
- It must be stressed that the dog is thoroughly saturated in a solution of the correct strength. It is imperative that all areas of the dog be soaked, including inside the ears and under the tail.
- A good method, advised to owners of groups of dogs such as stations or breeders or kennels, is to prepare a permanent solution in a bath made from half a 44-gallon drum and dunk the dogs in every week. A lid must be kept on to prevent contamination, deterioration or accidental poisoning by drinking.
- Bedding must be treated or destroyed at the same time and the dog’s premises should also be treated with the chemical wash.
- Treatment of the dog’s environment apart from its kennel or sleeping place is not very practical as the free-living ticks would be well scattered.
- Insecticide-impregnated collars have been made available for tick control. However, they do not appear to be as efficient as regular washes and may cause skin problems.
- Further advice or treatment can be obtained from any veterinary surgeon.